Joel Ullom

Publications

Approaches to the Optimal Nonlinear Analysis of Microcalorimeter Pulses

March 08, 2018

Author(s):

Joseph W. Fowler, Christine G. Pappas, Bradley K. Alpert, William B. Doriese, Galen C. O'Neil, Joel N. Ullom, Daniel S. Swetz

We consider how to analyze microcalorimeter pulses for quantities that are nonlinear in the data, while preserving the signal-to-noise advantages of linear...

L-Edge Spectroscopy of Dilute, Radiation-Sensitive Systems Using a Transition-Edge-Sensor Array

December 07, 2017

Author(s):

Daniel S. Swetz, William B. Doriese, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kelsey M. Morgan, Galen C. O'Neil, Joel N. Ullom

We present X-ray absorption spectroscopy and resonant inelastic X-ray scattering (RIXS) measurements on the iron L-edge of 0.5 mM aqueous ferricyanide. These...

Dependence of transition width on current and critical current in transition-edge sensors

December 07, 2017

Author(s):

Kelsey M. Morgan, Christine G. Pappas, Douglas A. Bennett, Johnathon D. Gard, James P. Hays-Wehle, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Daniel S. Swetz

If transition-edge sensor (TES) X-ray detectors are to be useful in photon-rich environments,they must maintain high resolving power when pulse durations are...

Simultaneous readout of 128 X-ray and Gamma-ray Transition-edge Microcalorimeters using Microwave SQUID Multiplexing

August 08, 2017

Author(s):

John A. Mates, Daniel T. Becker, Douglas A. Bennett, Johnathon D. Gard, James P. Hays-Wehle, Joseph W. Fowler, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Daniel S. Swetz, Leila R. Vale, Joel N. Ullom

The number of elements in most cryogenic sensor arrays is limited by the technology available to multiplex signals from the array into a smaller number of...

A Reassessment of Absolute Energies of X-ray L Lines of Lanthanide Metals

June 28, 2017

Author(s):

Bradley K. Alpert, William B. Doriese, Gene C. Hilton, Lawrence T. Hudson, Young Il Joe, Kelsey M. Morgan, Carl D. Reintsema, Daniel R. Schmidt, Daniel S. Swetz, Csilla I. Szabo-Foster, Joel N. Ullom, Joseph W. Fowler, Galen C. O'Neil, Douglas A. Bennett

We introduce a new technique for determining x-ray fluorescence line energies and widths, and we present measurements made with this technique of 22 x-ray L...